Pestera Closani (Mehedinti Mountains, SW Carpathians) is the laboratory cave of the ERIS. It is an inactive cave and a natural monument protected for its speleothems and large size calcite crystals as well as for its endemic fauna. The access is restricted to researchers only. It is monitored for microclimate, hydrology, geochemistry and stable isotopes in 6 stations where newly formed calcite is collected every 2 months. In Closani speleothems are studied for their potential of recording climate changes as this cave offers the best microclimatic conditions for calcite isotopic equilibrium deposition. This cave will be used as a “control cave” for assessing the effects of human visitation on cave microflora, calcite deposition rates, effects of condensation corrosion, etc.